NMR structures in different membrane environments of three ocellatin peptides isolated from Leptodactylus labyrinthicus

Publication date: Available online 26 March 2018 Source:Peptides Author(s): Karla A.G.G. Gomes, Daniel M. dos Santos, Virgílio M. Santos, Dorila Piló-Veloso, Higor M. Mundim, Leticia V. Rodrigues, Luciano M. Lião, Rodrigo M. Verly, Maria Elena de Lima, Jarbas M. Resende The peptides ocellatin-LB1, −LB2 and −F1 have previously been isolated from anurans of the Leptodactylus genus and the sequences are identical from residue 1 to 22, which correspond to ocellatin-LB1 sequence (GVVDILKGAAKDIAGHLASKVM-NH2), whereas ocellatin-LB2 carries an extra N and ocellatin-F1 extra NKL residues at their C-termini. These peptides showed different spectra of activities and biophysical investigations indicated a direct correlation between membrane-disruptive properties and antimicrobial activities, i.e. ocellatin-F1 > ocellatin-LB1 > ocellatin-LB2. To better characterize their membrane interactions, we report here the detailed three-dimensional NMR structures of these peptides in TFE-d 2:H2O (60:40) and in the presence of zwitterionic DPC-d 38 and anionic SDS-d 25 micellar solutions. Although the three peptides showed significant helical contents in the three mimetic environments, structural differences were noticed. When the structures of the three peptides in the presence of DPC-d 38 micelles are compared to each other, a more pronounced curvature is observed for ocellatin-F1 and the bent helix, with the concave face composed mostly of hydrophobic residues...
Source: Peptides - Category: Biochemistry Source Type: research